Summary
Highlights
This lesson focuses on strategies and interventions for elevated intra-abdominal pressure (IAP), intra-abdominal hypertension (IAH), and abdominal compartment syndrome (ACS). It highlights the importance of recognizing signs, staging risk, and identifying organ dysfunction. The management largely follows guidelines from the Abdominal Compartment Society, though not all recommendations are backed by strong evidence. Decisions shouldn't solely rely on IAP values, as conservative management might be appropriate even with ACS, and quick action might be needed for IAH cases before IAP reaches 20 mmHg. Key principles include serial IAP measurements, optimizing organ perfusion, identifying organ dysfunction, targeting IAP control, and timely surgical decompression.
For abdominal compartment syndrome, the primary treatment is surgical decompressive open abdomen with a temporary closure. This is crucial when organ dysfunction occurs due to high pressure. Prophylactic open abdomen procedures are common in trauma and abdominal surgery patients to prevent ACS by accommodating expected edema. However, refractory ACS can still occur, necessitating revision of the open abdomen. Surgical decompression is not without risks, including ventral hernia, enteric fistula, and intra-abdominal sepsis, which increase morbidity and decrease quality of life. Therefore, surgery is reserved for warranted cases.
Before ACS, non-surgical interventions aim to reduce IAP. The algorithm starts by checking if IAP is >12 mmHg. If so, treatments to reduce IAP and optimize organ perfusion are initiated. The patient is then checked for IAP >20 mmHg with new organ dysfunction. If not, IAP is monitored every 4-6 hours (or continuously). If IAP consistently falls below 12 mmHg, IAH is considered resolved, and measurements are discontinued. If IAP >20 mmHg and new organ dysfunction are present, the patient has ACS. The type of ACS (primary, secondary, or recurrent) is assessed. If primary, surgical decompression is warranted. For secondary or recurrent ACS, the presence of new or progressive organ failure determines if surgical decompression is needed. Otherwise, medical interventions and serial IAP monitoring continue. If IAP remains >12 mmHg, the process repeats; if it drops below 12 mmHg, IAH is resolved.
Medical management involves a stepwise approach if IAP worsens. One arm is evacuating interluminal contents to reduce intestinal volume and thus IAP. This begins with nasogastric or rectal tube decompression. Medications like metoclopramide or erythromycin for gastric motility, and polyethylene glycol or senna for colonic motility, are then considered. Minimize enteral nutrition and flushes, and use enemas. If unimproved, colonoscopic decompression is an option, followed by discontinuing all enteral nutrition. If IAP remains >20 mmHg with new organ dysfunction despite these measures, surgical decompression is the next step.
Another strategy is evacuating intra-abdominal space-occupying lesions such as fluid collections (bleeding, ascites, pancreatitis, abscesses), tumors, or hernias. Initial steps involve identifying lesions via abdominal ultrasound, followed by a CT scan for better identification. If appropriate, percutaneous catheter drainage of the lesion is attempted. If ineffective or not feasible, surgical evacuation of the lesion follows. Again, if IAP remains >20 mmHg with new organ dysfunction, surgical decompression is considered.
Improving abdominal wall compliance allows better compensation for elevated IAP. Strategies include adequate sedation and analgesia, removing constrictive dressings, and addressing abdominal scars. Keeping the head of the bed no higher than 30 degrees, or even lying the patient flat or in Trendelenburg, can help. Finally, paralytics may be used to fully relax the abdominal wall. If IAP remains >20 mmHg with new organ dysfunction, surgical decompression is the next intervention.
Optimizing fluid balance involves avoiding excessive fluid resuscitation, aiming initially for a zero or slightly negative fluid balance. If IAP remains elevated, hypertonic fluids and colloids may be used. Once stable, fluid removal via diuretics, dialysis, ultrafiltration, or CRRT is considered. Optimizing systemic and regional perfusion ensures adequate blood flow and oxygen delivery to organs. This includes goal-directed fluid resuscitation to increase cardiac output, optimizing ventilation and alveolar recruitment for oxygen delivery, and using hemodynamic monitoring to guide resuscitation. Vasopressors and inotropes may be necessary for adequate perfusion. If IAP remains >20 mmHg with new organ dysfunction, surgical decompression is strongly considered.